Surface area of fixtures

ABSTRACT

A method and apparatus. The apparatus comprises a first portion of a tool and a second portion of the tool. The first portion of the tool has a first surface. The first surface has a shape that is complementary to a first portion of a part. The second portion has at least one of a second surface configured to be recessed from a second portion of the part or a hollow portion.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional application of, and claims priority to,U.S. patent application Ser. No. 14/711,021, filed May 13, 2015, andissued a Notice of Allowance dated Mar. 23, 2020. The contents of U.S.patent application Ser. No. 14/711,021 are therefore incorporated hereinin their entirety.

BACKGROUND INFORMATION 1. Field

The present disclosure relates generally to the surface area offixtures. More particularly, the present disclosure relates to millingfixtures. The present disclosure relates still more particularly tomethods and apparatuses for milling fixtures with reduced surface areacontact with a part.

2. Background

To perform milling operations on a part, the part may first be fittedand secured to a milling fixture. The milling fixture may providesupport to the part during the milling operations. A conventionalmilling fixture has a surface area that is complementary to a surface ofthe part. As a result, during milling operations, the surface of thepart may contact all of the surface area of the milling fixture.

For substantially large parts, it may be more difficult than desired tocause the surface of the part to completely contact the surface area ofthe milling fixture. Further, placing the surface of the part intocomplete contact with the surface area of the milling fixture mayrequire at least one of an undesirable amount of time, a force, or anumber of operators. In some cases, placing the surface of the part intocomplete contact with the surface area of the milling fixture may causeinconsistencies in the part due to undesirable forces placed upon thepart. For example, for large parts, operators may stand or sit on theparts to place the surface of the parts into contact with the surfacearea of the milling fixture. Standing or sitting on the parts may causeout of tolerance conditions or inconsistencies in the parts.

Therefore, it would be desirable to have a method and apparatus thattake into account at least some of the issues discussed above, as wellas other possible issues.

SUMMARY

An illustrative embodiment of the present disclosure provides anapparatus. The apparatus comprises a first portion of a tool and asecond portion of the tool. The first portion of the tool has a firstsurface. The first surface has a shape that is complementary to a firstportion of a part. The second portion has at least one of a secondsurface configured to be recessed from a second portion of the part or ahollow portion.

Another illustrative embodiment of the present disclosure provides anapparatus. The apparatus comprises a part support surface of a tool, arecessed surface of the tool, and a number of vacuum ports disposedwithin the part support surface.

A further illustrative embodiment of the present disclosure provides amilling fixture. The milling fixture comprises a surface configured tosupport a part during a milling operation. The surface differs from aforming surface of a forming fixture by at least one of a recessedportion or a hollow portion.

A yet further illustrative embodiment of the present disclosure providesa method of creating a milling fixture. A first surface of a tool ismanufactured. The first surface has a shape that is complementary to afirst portion of a part. A second surface of the tool is manufactured.The second surface is configured to be recessed from a second portion ofthe part.

Another illustrative embodiment of the present disclosure provides amethod of performing a milling operation. A part is placed onto a toolsuch that a first portion of the part contacts a first surface of thetool and a second portion of the part does not contact a second portionof the tool. The first surface has a shape that is complementary to thefirst portion of the part. The second portion of the tool has at leastone of a second surface configured to be recessed from the secondportion of the part or a hollow portion. The first portion of the partis held against the first surface of the tool. A number of millingoperations are performed on the part.

The features and functions can be achieved independently in variousembodiments of the present disclosure or may be combined in yet otherembodiments in which further details can be seen with reference to thefollowing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the illustrativeembodiments are set forth in the appended claims. The illustrativeembodiments, however, as well as a preferred mode of use, furtherobjectives and features thereof, will best be understood by reference tothe following detailed description of an illustrative embodiment of thepresent disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an illustration of an aircraft in accordance with anillustrative embodiment;

FIG. 2 is an illustration of a block diagram of a manufacturingenvironment in accordance with an illustrative embodiment;

FIG. 3 is an illustration of an isometric view of a forming fixture inaccordance with an illustrative embodiment;

FIG. 4 is an illustration of an isometric view of a milling fixture inaccordance with an illustrative embodiment;

FIG. 5 is an illustration of an isometric view of a part created usingthe forming fixture and the milling fixture in accordance with anillustrative embodiment;

FIG. 6 is an illustration of an isometric view of a milling fixture inaccordance with an illustrative embodiment;

FIG. 7 is an illustration of an isometric view of a part created usingthe forming fixture and the milling fixture in accordance with anillustrative embodiment;

FIG. 8 is an illustration of a front cross-sectional view of a part inthe milling fixture in accordance with an illustrative embodiment;

FIG. 9 is an illustration of a flowchart of a process for creating amilling fixture in accordance with an illustrative embodiment;

FIG. 10 is an illustration of a flowchart of a process for performing amilling operation in accordance with an illustrative embodiment;

FIG. 11 is an illustration of a block diagram of an aircraftmanufacturing and service method in accordance with an illustrativeembodiment; and

FIG. 12 is an illustration of a block diagram of an aircraft in which anillustrative embodiment may be implemented.

DETAILED DESCRIPTION

The different illustrative embodiments recognize and take into account anumber of different considerations. As used herein, “a number of items”means one or more items. For example, “a number of differentconsiderations” means one or more considerations.

The illustrative embodiments recognize and take into account thatconventional milling fixtures have surfaces that are complementary to arespective part. The illustrative embodiments recognize and take intoaccount that the entirety of a surface of a conventional milling fixturemay contact the part during a milling operation. The illustrativeembodiments further recognize and take into account that at least one ofless time, less force, or fewer operators may be used to place a partonto a milling fixture when a reduced surface area of the part contactsthe part. By reducing the surface area of the part, placing the partonto the milling fixture may take at least one of less time, less force,or less operators. The illustrative embodiments also recognize and takeinto account that having a milling fixture with reduced surface areacontacting the part may result in fewer inconsistencies in the part.

As used herein, the phrase “at least one of,” when used with a list ofitems, means different combinations of one or more of the listed itemsmay be used and only one of each item in the list may be needed. Forexample, “at least one of item A, item B, or item C” may include,without limitation, item A, item A and item B, or item B. This examplealso may include item A, item B, and item C or item B and item C. Ofcourse, any combinations of these items may be present. In otherexamples, “at least one of” may be, for example, without limitation, twoof item A; one of item B; and ten of item C; four of item B and seven ofitem C; or other suitable combinations. The item may be a particularobject, thing, or a category. In other words, at least one of means anycombination items and number of items may be used from the list but notall of the items in the list are required.

With reference now to the figures, and in particular, with reference toFIG. 1, an illustration of an aircraft is depicted in accordance with anillustrative embodiment. In this illustrative example, aircraft 100 haswing 102 and wing 104 attached to body 106. Aircraft 100 includes engine108 attached to wing 102 and engine 110 attached to wing 104.

Body 106 has tail section 112. Horizontal stabilizer 114, horizontalstabilizer 116, and vertical stabilizer 118 are attached to tail section112 of body 106.

Aircraft 100 is an example of an aircraft having components which may bemanufactured in accordance with an illustrative embodiment. For example,body 106 of aircraft 100 may have a passenger cabin that includescomponents processed using milling fixtures. As one example, portions ofbody 106 may be processed using milling fixtures. As another example,portions of wing 102 or wing 104 may be processed using millingfixtures.

This illustration of aircraft 100 is provided for purposes ofillustrating one environment in which the different illustrativeembodiments may be implemented. The illustration of aircraft 100 in FIG.1 is not meant to imply architectural limitations as to the manner inwhich different illustrative embodiments may be implemented. Forexample, aircraft 100 is shown as a commercial passenger aircraft. Thedifferent illustrative embodiments may be applied to other types ofaircraft, such as private passenger aircraft, a military aircraft, arotorcraft, and other suitable types of aircraft. For example, anillustration of a block diagram of aircraft 1100 is depicted in FIG. 11.

Although the illustrative examples for an illustrative embodiment aredescribed with respect to an aircraft, the illustrative embodiment maybe applied to other types of platforms. The platform may be, forexample, a mobile platform, a stationary platform, a land-basedstructure, an aquatic-based structure, and a space-based structure. Morespecifically, the platform may be a surface ship, a tank, a personnelcarrier, a train, a spacecraft, a space station, a satellite, asubmarine, an automobile, and other suitable platforms.)

Turning now to FIG. 2, an illustration of a block diagram of amanufacturing environment is depicted in accordance with an illustrativeembodiment. Manufacturing environment 200 may be used to manufacturePart 202. Part 202 may be a part of aircraft 204. Aircraft 100 of FIG. 1may be a physical implementation of aircraft 204 of FIG. 2.

Part 202 may be made of at least one of polymer 206, metal 208, orcomposite material 210. Part 202 may be manufactured and then milled.Part 202 may be manufactured using at least one of machining, sintering,molding, bending, printing, laying up, welding, friction stir welding,additive manufacturing, or other desirable manufacturing processes. Forexample, when part 202 is made of polymer 206, part 202 may bemanufactured by molding or printing polymer 206. As another example,when part 202 is made of metal 208, part 202 may be manufactured bymachining metal 208. In illustrative examples in which part 202 is madeof composite material 210, composite material 210 may be laid up onforming fixture 212. Forming fixture 212 may be configured to form part202. Forming fixture 212 may have forming surface 214. Forming surface214 may be used to shape composite material 210 into part 202.

When forming fixture 212 is concave 216, forming fixture 212 may be usedto form a substantially convex surface of part 202. As a result, part202 may have a substantially convex surface complementary to formingsurface 214 of forming fixture 212. When forming fixture 212 is convex218, forming fixture 212 may be used to form a substantially concavesurface of part 202. As a result, part 202 may have a substantiallyconcave surface complementary to forming surface 214 of forming fixture212.

For milling operations such as milling operation 219, part 202 may besupported by tool 220. In some illustrative examples, tool 220 may bemilling fixture 222. Tool 220 may have surface 224. Surface 224 may beconfigured to support part 202 during milling operation 219. Surface 224may differ from forming surface 214 of forming fixture 212 by at leastone of recessed portion 226 or hollow portion 228.

First portion 230 of tool 220 may have first surface 232. First surface232 may have shape 233 that is complementary to first portion 234 ofpart 202. In some illustrative examples, first surface 232 may bereferred to as part support surface 235. Tool 220 may also have secondportion 236. Second portion 236 may have at least one of second surface238 configured to be recessed from second portion 240 of part 202, orhollow portion 228. In some illustrative examples, second surface 238may be configured to be recessed from second portion 240 of part 202 andmay be referred to as recessed surface 242. In some illustrativeexamples, recessed surface 242 may be radiused surface 243.

First surface area 244 of milling fixture 222 may be a portion ofsurface area 246 of milling fixture 222 that contacts part 202 tosupport part 202 during milling operation 219. In some illustrativeexamples, first surface area 244 of milling fixture 222 contacting part202 is less than second surface area 248 of forming fixture 212contacting part 202.

In some illustrative examples, first surface 232 may be substantiallythe same as first forming surface 250 of forming fixture 212 configuredto form part 202. First forming surface 250 of forming fixture 212 maybe used to form first portion 234. First forming surface 250 may becomplementary to first portion 234 of part 202. Second surface 238 maydiffer from second forming surface 252 of forming fixture 212. Secondsurface 238 may differ from second forming surface 252 of formingfixture 212 by at least one of recessed portion 226 or hollow portion228. Tool 220 may differ from forming surface 214 of forming fixture 212by at least one of recessed surface 242 or hollow portion 228.

Although tool 220 has been discussed relative to forming fixture 212,part 202 may be manufactured using any of a number of manufacturingprocesses. In some illustrative examples, part 202 may not bemanufactured using forming fixture 212. For example, part 202 may bemanufactured using at least one of bending, machining, printing,sintering, printing, welding, friction stir welding, additivemanufacturing, chemical milling, joining, or other desirablemanufacturing processes. In these illustrative examples, tool 220 mayinstead be described relative to part 202.

Surface 224 may be designed to support part 202. Further, surface 224may be designed such that placing part 202 onto tool 220 may not use anundesirable amount of force. Surface 224 may be designed such that onlya fraction of surface 224 contacts part 202. This fraction may bereferred to as first surface 232 of first portion 230 of tool 220. Firstsurface area 244 may be an area of tool 220 contacting part 202.

First surface 232 may be designed for desirable placement of part 202 ontool 220. Further, first surface 232 may be designed for desirablequality of part 202 following milling operation 219. First surface 232may be sufficient to support part 202 without undesirable vibrationduring milling operation 219. Undesirable vibration may cause out oftolerance conditions or inconsistencies in at least one of part 202 ortool 220. Tool 220 may be designed such that support of part 202 bysecond surface 238 is not required for milling operation 219. Secondsurface 238 may not be required to contact part 202 to reduce oreliminate vibration during milling operation 219.

Second portion 236 of tool 220 may not contact part 202. Second portion236 of tool 220 may not contact part 202 because recessed surface 242may be recessed from second portion 240 of part 202. In someillustrative examples, second portion 236 of tool 220 may not contactpart 202 because hollow portion 228 may be present in second portion236. Hollow portion 228 may be a section of tool 220 in which there isnot material. In some illustrative examples, hollow portion 228 may becutout within surface 224 of tool 220.

It may be desirable to not only maintain the quality of part 202 byreducing or preventing inconsistencies, but it may also be desirable tomaintain the structural stability of milling fixture 222. Surface area246 may be sufficient to maintain structural stability of millingfixture 222. Further, mass 254 of milling fixture 222 may be sufficientto maintain structural stability of milling fixture 222.

When part 202 is concave 256 or convex 258, tolerance stack up orvariances in manufacturing of part 202 may make fitting part 202 to aconventional milling fixture more difficult than desired. However, byhaving second portion 236, tolerance stack up or variances in secondportion 240 of part 202 may not influence fitting part 202 onto tool220. Second portion 236 may reduce at least one of time or force to fitpart 202 to tool 220.

After placing part 202 onto tool 220, part 202 may be held onto tool 220by drawing a vacuum on first portion 234 of part 202. Vacuum generator260 may apply a vacuum to number of vacuum ports 262 to hold firstportion 234 of part 202 against first surface 232 of tool 220. Number ofvacuum ports 262 may be disposed within first surface 232 of tool 220.

Part 202 may not contact second portion 236. As a result, second portion236 may not be associated with any vacuum ports.

By reducing the amount of surface 224 contacting part 202, at least oneof the time, force, or number of operators to fit part 202 to tool 220may be reduced. Further, by reducing the amount of surface 224contacting part 202, at least one of the manufacturing time orinspection time for manufacturing tool 220 may be reduced. For example,by reducing the amount of surface 224 contacting part 202, the amount ofsurface 224 having tight tolerance machining and inspection steps may bereduced.

Tool 220 is formed of material 263. In some illustrative examples, tool220 may be formed of at least one of composite material 264, metal 266,or other desirable material. When tool 220 is formed of metal 266, firstsurface 232 and second surface 238 may be manufactured by machiningmetal 266. When tool 220 is formed of composite material 264, firstsurface 232 and second surface 238 may be formed by laying up compositematerial 264 on forming fixture 212, curing composite material 264, andmachining composite material 264.

As described above, second portion 236 of tool 220 may not contact part202 because recessed surface 242 may be recessed from second portion 240of part 202. Part 202 may be formed using manufacturing process 268.Manufacturing process 268 may have tolerance 270. Due to tolerance 270,part 202 may have an acceptable variation in size, shape, or othercharacteristics.

Part 202 may have designed parameters 272. Surface 274 of part 202 mayvary from designed parameters 272 due to tolerance 270. In someillustrative examples, the combination of tolerance 270 and designedparameters 272 may describe the maximum growth of part 202. It may bedesirable for second surface 238 to not contact part 202.

Second surface 238 may be recessed taking tolerance 270 into account. Insome illustrative examples, second surface 238 may be recessed greaterthan the maximum growth of part 202. By having a greater recess than themaximum growth of part 202, second surface 238 may not contact part 202even if second portion 240 has full tolerance 270.

In some illustrative examples, second surface 238 is recessed fromdesigned parameters 272 of part 202 a value greater than the value oftolerance 270 for manufacturing process 268 utilized to manufacture part202. In these illustrative examples, difference 276 between secondsurface 238 and second portion 240 may be greater than zero. Bydifference 276 between second surface 238 and second portion 240 beinggreater than zero, second surface 238 may not contact second portion240.

In some illustrative examples, difference 278 between second surface 238and second forming surface 252 is greater than tolerance 270. Whendifference 278 is greater than tolerance 270, second surface 238 may notcontact second portion 240 of part 202. When second surface 238 does notcontact second portion 240 of part 202, seating part 202 on millingfixture 222 may require at least one of less force, less time, or feweroperators.

In some illustrative examples, milling operation 219 may be performed onfirst portion 234 of part 202. When milling operation 219 is a drillingoperation, milling operation 219 may be performed through holes 279 infirst surface 232. First surface 232 may be positioned relative to firstportion 234 of part 202 that will receive milling operation 219.

Second portion 240 may not receive milling operation 219. In someillustrative examples, second surface 238 may be desirably placedrelative to second portion 240 when second portion 240 does not receivemilling operation 219.

In some illustrative examples, second surface 238 may be locatedrelative to portions of part 202 that may have the greatest expectedvariation. For example, second surface 238 may be radiused surface 280.When second surface 238 is radiused surface 280, second portion 240 maybe radiused surface 282. Radiused surface 282 may vary from designedparameters 272 more frequently or a greater amount than first portion234 varies from designed parameters 272.

Turning now to FIG. 3, an illustration of an isometric view of a formingfixture is depicted in accordance with an illustrative embodiment.Forming fixture 300 may be a physical implementation of forming fixture212 of FIG. 2. Forming fixture 300 may be substantially concave 302.Forming fixture 300 may act as an outer mold line when forming a part.In this illustrative example, forming fixture 300 has forming surface304. Forming surface 304 includes first forming surface 306 and secondforming surface 308. Forming surface 304 has surface area 310. Surfacearea 310 may be the value of the area of forming surface 304 contactinga part during forming.

Turning now to FIG. 4, an illustration of an isometric view of a millingfixture is depicted in accordance with an illustrative embodiment.Milling fixture 400 may be a physical implementation of milling fixture222 of FIG. 2. In some illustrative examples, milling fixture 400 maysupport a part formed using forming fixture 300 during a millingoperation such as milling operation 219 of FIG. 2. In some illustrativeexamples, milling fixture 400 may support a part manufactured using anydesirable manufacturing process during a milling operation.

Milling fixture 400 has surface 402. Surface 402 may be configured tosupport a part during a milling operation. Surface 402 has first portion404 and second portion 406. First portion 404 includes first surface 408that may be configured to contact a portion of a part during a millingoperation. First surface 408 has holes 409 through which a millingoperation such as milling operation 219 of FIG. 2 may be performed. Forexample, a drill bit (not depicted) may go at least partway throughholes 409 to perform a milling operation. First portion 404 may beassociated with number of vacuum ports 410. Number of vacuum ports 410is disposed within first surface 408. Number of vacuum ports 410 mayapply a vacuum to hold a portion of the part against first surface 408of milling fixture 400. In this illustrative example, number of vacuumports 410 is a single vacuum port. However, in other illustrativeexamples, number of vacuum ports 410 may be more than one vacuum port.Number of vacuum ports 410 may include any desirable number of vacuumports for milling fixture 400. A desirable number of vacuum ports may bedetermined based on at least one of locations of number of vacuum ports410, size of first portion 404, shape of first portion 404, size ofsecond portion 406, shape of second portion 406, location of secondportion 406 relative to first portion 404, or other considerations.

In this illustrative example, second portion 406 includes recessedportion 412, recessed portion 414, recessed portion 416, recessedportion 418, hollow portion 420, hollow portion 422, and hollow portion424. Recessed portion 412, recessed portion 414, recessed portion 416,and recessed portion 418 are configured to be recessed from a secondportion of a part to be positioned on milling fixture 400. In someillustrative examples, recessed portion 412, recessed portion 414,recessed portion 416, and recessed portion 418 may each be recessed fromthe part substantially the same distance. In some illustrative examples,at least one of recessed portion 412, recessed portion 414, recessedportion 416, or recessed portion 418 may be recessed from the part adifferent value than the other recessed portions. In some illustrativeexamples, at least one of recessed portion 412, recessed portion 414,recessed portion 416, or recessed portion 418 may be recessed a valuegreater than the maximum growth of the part. In some illustrativeexamples, at least one of recessed portion 412, recessed portion 414,recessed portion 416, or recessed portion 418 may be recessed from thepart a value greater than a tolerance value for a manufacturing processutilized to manufacture the part.

First surface 408 of milling fixture 400 may be substantially the sameas first forming surface 306 of forming fixture 300 of FIG. 3. Secondportion 406 of milling fixture 400 may differ from second formingsurface 308 of forming fixture 300 of FIG. 3 as a result of recessedportion 412, recessed portion 414, recessed portion 416, recessedportion 418, hollow portion 420, hollow portion 422, and hollow portion424. Second portion 406 of milling fixture 400 does not contact the partduring a milling operation.

Other components may be present in milling fixture 400 which are notdepicted herein. For example, when milling fixture 400 includes numberof vacuum ports 410, milling fixture 400 may also include a number ofrubber seals. The number of rubber seals may create barriers forcontaining the vacuum. As another example, when milling fixture 400includes number of vacuum ports 410, milling fixture 400 may alsoinclude vacuum grooves to improve air flow between milling fixture 400and a part (not depicted). A number of vacuum grooves or passages mayact as guides or supply vessels for the vacuum under the part.

In other illustrative examples, milling fixture 400 may not beassociated with a vacuum generator. In these illustrative examples,milling fixture 400 may not have number of vacuum ports 410. In theseillustrative examples, vacuum may not be used to maintain a position ofa part on milling fixture 400. In these illustrative examples, analternative method of maintaining the position of a part on millingfixture 400 may be used. An alternate method of maintaining the positionof a part on milling fixture 400 may include at least one of bolts,screws, clamps, double back tape, adhesives, or any other desirablecomponents for retaining the position of part. For example, clamps (notdepicted) may be used to maintain a position of a part on millingfixture 400. In this illustrative example, the part (not depicted) maybe clamped after the part (not depicted) is seated on milling fixture400.

Turning now to FIG. 5, an illustration of an isometric view of a partcreated using the forming fixture and the milling fixture is depicted inaccordance with an illustrative embodiment. Part 500 may be a physicalimplementation of part 202 of FIG. 2. Part 500 may be formed usingforming fixture 300 of FIG. 3 and may be milled while on milling fixture400 of FIG. 4.

Part 500 has first portion 502 and second portion 504. First portion 502may contact first surface 408 of milling fixture 400 of FIG. 4 during amilling operation. Second portion 504 may not contact milling fixture400 during a milling operation. Holes 506 within first portion 502 maybe examples of features formed during a milling operation. Holes 506 maybe formed by drilling through first portion 404 of milling fixture 400of FIG. 4. Accordingly, holes 506 may substantially match locations ofholes 409 of milling fixture 400 of FIG. 4. Holes 506 may extend acrossthe dome and around the perimeter of part 500.

Turning now to FIG. 6, an illustration of an isometric view of a millingfixture is depicted in accordance with an illustrative embodiment.Milling fixture 600 may be a physical implementation of milling fixture222 of FIG. 2. Milling fixture 600 may be used to perform a millingoperation on a part, such as a car bumper.

Milling fixture 600 has surface 602 including first portion 604 andsecond portion 606. First portion 604 includes first surface 608. Firstsurface 608 may contact a portion of a part (not depicted) during amilling operation such as milling operation 219 of FIG. 2. Secondportion 606 may include recessed portion 610. Although second portion606 is depicted as only including one recessed portion, second portion606 may include any desirable number of recessed portions. For example,second portion 606 may include at least one hollow portion and norecessed portions. In some illustrative examples, second portion 606 mayinclude more than one recessed portion. In some illustrative examples,rather than recessed portion 610 being continuous, the area covered byrecessed portion 610 may be subdivided into separate recessed portions.

Second portion 606 may not contact the part during a milling operation.Recessed portions such as recessed portion 610 may be desirably locatedin rounded or radiused areas of milling fixture 600. Substantiallyplanar areas may be desirably within first portion 604 of millingfixture 600. Rounded or radiused areas of parts may be more likely toinclude out of tolerance conditions such as out of tolerance shape,thickness, or other characteristics. Rounded or radiused areas of partsmay be more likely to vary from designed parameters of the part.Substantially planar areas of parts may be less likely to include out oftolerance characteristics.

In some illustrative examples, recessed portion 610 may be recessed fromthe part substantially the same distance throughout recessed portion610. In some illustrative examples, at least one area of recessedportion 610 may be recessed from the part a different value than anotherarea of recessed portion 610. For example, the depth of recessed portion610 may vary over the length of recessed portion 610. In someillustrative examples, recessed portion 610 may be recessed a valuegreater than the maximum growth of the part. In some illustrativeexamples, recessed portion 610 may be recessed from the part a valuegreater than a tolerance value for a manufacturing process utilized tomanufacture the part.

First portion 604 may be associated with a number of vacuum ports (notdepicted). The number of vacuum ports (not depicted) may be disposed infirst surface 608. A vacuum may be drawn through the number of vacuumports (not depicted) to hold a portion of the part against first portion604 of milling fixture 600. Second portion 606 may not be associatedwith any vacuum ports.

Turning now to FIG. 7, an illustration of an isometric view of a partcreated using the forming fixture and the milling fixture is depicted inaccordance with an illustrative embodiment. Part 700 may be a physicalimplementation of part 202 of FIG. 2. Part 700 may be milled while onmilling fixture 600 of FIG. 6. In some illustrative examples, part 700may be a composite material. In these illustrative examples, part 700may be formed on a forming tool (not depicted). In some illustrativeexamples, part 700 may be a metal. In these illustrative examples, part700 may be manufactured by at least one of bending or machining.

Part 700 may have first portion 702 and second portion 704. Firstportion 702 may be in contact with first portion 604 of milling fixture600 of FIG. 6 during a milling operation. Second portion 704 may not bein contact with milling fixture 600 during a milling operation.

Surface 602 of milling fixture 600 may be designed such that part 700may be sufficiently supported during a milling operation. For example,surface 602 of milling fixture 600 may be designed such that firstsurface 608 may be sufficient to support part 700 without undesirablevibration during a milling operation. Surface 602 of milling fixture 600may be designed such that support of second portion 704 by secondportion 606 is not required for a milling operation.

Holes 706 within first portion 702 may be examples of features formedduring a milling operation. Holes 706 may be formed by drilling throughfirst portion 604 of milling fixture 600 of FIG. 6. Another illustrativeexample of a milling operation may be a trimming operation. For example,edge 708 of part 700 may be trimmed while part 700 is on milling fixture600. In some illustrative examples, other milling operations may beperformed on part 700 while part 700 is on milling fixture 600.

Turning now to FIG. 8, an illustration of a front cross-sectional viewof a part in the milling fixture is depicted in accordance with anillustrative embodiment. View 800 may be a front cross-sectional view ofpart 700 within milling fixture 600 seen in direction of lines 8-8 inFIG. 6.

As depicted, milling fixture 600 has recessed portion 610. Secondportion 606 may include recessed portion 610. As depicted, recessedportion 610 does not contact part 700.

Second portion 704 of part 700 does not contact milling fixture 600.Second portion 704 may include at least one of radiused portion 804,radiused portion 806, or radiused portion 808. For example, radiusedportion 804 does not contact recessed portion 610. In some illustrativeexamples, second portion 704 may include radiused portion 804. Radiusedportion 806 does not contact recessed portion 610. In some illustrativeexamples, second portion 704 may include radiused portion 806. Radiusedportion 808 does not contact recessed portion 610. In some illustrativeexamples, second portion 704 may include radiused portion 808.

In this illustrative example, first portion 702 of part 700 contactsfirst portion 604 of milling fixture 600. First portion 702 may includeat least one of section 810, section 812, section 814, or section 816.First portion 604 of milling fixture 600 may include at least one ofsection 818, section 820, section 822, or section 824. Section 810 maycontact section 818 of milling fixture 600. Section 812 may contactsection 820 of milling fixture 600. Section 814 may contact section 822of milling fixture 600. Section 816 may contact section 824 of millingfixture 600.

The diagrammatic representation of aircraft 100 in FIG. 1, manufacturingenvironment 200 in FIG. 2, forming fixture 300 in FIG. 3, millingfixtures in FIGS. 4, 6, and 8, and parts in FIGS. 5, 7, and 8 are notmeant to imply physical or architectural limitations to the manner inwhich an illustrative embodiment may be implemented. Other components inaddition to or in place of the ones illustrated may be used. Somecomponents may be unnecessary. Also, the blocks of FIG. 2 are presentedto illustrate some functional components. One or more of these blocksmay be combined, divided, or combined and divided into different blockswhen implemented in an illustrative embodiment.

For example, second portion 236 may include more than one recessedportion. As another example, second portion 236 may include more thanone hollow portion. In yet another example, hollow portion 228 may notbe present.

Turning now to FIG. 9, an illustration of a flowchart of a process forcreating a milling fixture is depicted in accordance with anillustrative embodiment. Process 900 may be used to form milling fixture222 of FIG. 2.

Process 900 may begin by manufacturing a first surface of a tool, inwhich the first surface has a shape that is complementary to a firstportion of a part (operation 902). In some illustrative examples,manufacturing the first surface of the tool may be done by at least oneof machining, laying up a material, printing, or other desirablemanufacturing processes. For example, in some illustrative examples,manufacturing the first surface includes laying up a composite material.

Process 900 may then manufacture a second surface of the tool, in whichthe second surface is configured to be recessed from a second portion ofthe part (operation 904). In some illustrative examples, the secondsurface of the tool is a radiused surface of the tool. In someillustrative examples, the second portion of the part does not receive amilling operation. Afterwards the process may terminate.

In some illustrative examples, manufacturing the second surface of thetool may be done by at least one of machining, laying up a material,printing, or other desirable manufacturing process. In otherillustrative examples, manufacturing the first surface and manufacturingthe second surface comprises laying up a composite material. In someillustrative examples, manufacturing the first surface and manufacturingthe second surface comprises machining a material. In some illustrativeexamples, the material may be a metal. In some other illustrativeexamples, the material may be a composite material.

In some illustrative examples, manufacturing the second surface of thetool may include removing a portion of the second surface to form ahollow portion. In some illustrative examples, manufacturing the firstsurface may occur after manufacturing the second surface. For example,the first surface may be formed through additive manufacturing. Thefirst surface may be additively created onto a base having the secondsurface. In some illustrative examples, manufacturing the second surfaceof the tool may include forming a hollow portion by not laying upmaterial in the hollow portion.

Turning now to FIG. 10, an illustration of a flowchart of a process forperforming a milling operation is depicted in accordance with anillustrative embodiment. Process 1000 may be used to perform a millingoperation on part 202 of FIG. 2.

Process 1000 may begin by placing a part onto a tool such that a firstportion of the part contacts a first surface of the tool and a secondportion of the part does not contact a second portion of the tool, inwhich the first surface has a shape that is complementary to the firstportion of the part, and in which the second portion of the tool has atleast one of a second surface configured to be recessed from the secondportion of the part or a hollow portion (operation 1002). The part maybe fitted to the tool using a desirable amount of force. By onlycontacting the first surface of the tool, the time to fit the part tothe tool may be less than if the entirety of the part were to contactthe milling fixture.

Process 1000 may also hold the first portion of the part against thefirst surface of the tool (operation 1004). Holding the first portion ofthe part against the first surface of the tool may be performed bydrawing a vacuum through a number of vacuum ports, clamping using anumber of clamps, or any other desirable method of holding the firstportion of the part against the first surface of the tool.

Process 1000 may also perform a number of milling operations on the part(operation 1006). In some illustrative examples, the number of millingoperations may include at least one of trimming or drilling. Afterwards,the process may terminate.

The flowcharts and block diagrams in the different depicted embodimentsillustrate the architecture, functionality, and operation of somepossible implementations of apparatuses and methods in an illustrativeembodiment. In this regard, each block in the flowcharts or blockdiagrams may represent a module, a segment, a function, and/or a portionof an operation or step.

In some alternative implementations of an illustrative embodiment, thefunction or functions noted in the blocks may occur out of the ordernoted in the Figures. For example, in some cases, two blocks shown insuccession may be executed substantially concurrently, or the blocks maysometimes be performed in the reverse order, depending upon thefunctionality involved. Also, other blocks may be added in addition tothe illustrated blocks in a flowchart or block diagram. Further, someblocks may not be implemented.

Illustrative embodiments of the disclosure may be described in thecontext of aircraft manufacturing and service method 1100 as shown inFIG. 11 and aircraft 1200 as shown in FIG. 12. Turning first to FIG. 11,an illustration of an aircraft manufacturing and service method isdepicted in accordance with an illustrative embodiment. Duringpre-production, aircraft manufacturing and service method 1100 mayinclude specification and design 1102 of aircraft 1200 of FIG. 12 andmaterial procurement 1104.

During production, component and subassembly manufacturing 1106 andsystem integration 1108 of aircraft 1200 of FIG. 12 takes place.Thereafter, aircraft 1200 of FIG. 12 may go through certification anddelivery 1110 in order to be placed in service 1112. While in service1112 by a customer, aircraft 1200 of FIG. 12 is scheduled for routinemaintenance and service 1114, which may include modification,reconfiguration, refurbishment, and other maintenance or service.

Each of the processes of aircraft manufacturing and service method 1100may be performed or carried out by a system integrator, a third party,and/or an operator. In these examples, the operator may be a customer.For the purposes of this description, a system integrator may include,without limitation, any number of aircraft manufacturers andmajor-system subcontractors; a third party may include, withoutlimitation, any number of vendors, subcontractors, and suppliers; and anoperator may be an airline, a leasing company, a military entity, aservice organization, and so on.

With reference now to FIG. 12, an illustration of an aircraft isdepicted in which an illustrative embodiment may be implemented. In thisexample, aircraft 1200 is produced by aircraft manufacturing and servicemethod 1100 of FIG. 11 and may include airframe 1202 with plurality ofsystems 1204 and interior 1206. Examples of systems 1204 include one ormore of propulsion system 1208, electrical system 1210, hydraulic system1212, and environmental system 1214. Any number of other systems may beincluded. Although an aerospace example is shown, different illustrativeembodiments may be applied to other industries, such as the automotiveindustry.

Apparatuses and methods embodied herein may be employed during at leastone of the stages of aircraft manufacturing and service method 1100 ofFIG. 11. One or more illustrative embodiments may be used duringcomponent and subassembly manufacturing 1106. For example, millingfixture 222 of FIG. 2 may be used during component and subassemblymanufacturing 1106. Further, part 202 of FIG. 2 may also be used toperform replacements during maintenance and service 1114. For example,aircraft 1200 may be inspected during scheduled maintenance for aircraft1200 and part 202 may be used to replace a part. Milling fixture 222 ofFIG. 2 may be used to secure any desirable types of parts, such ascomponents of airframe 1202 or interior 1206.

The illustrative embodiments present a milling fixture having a reducedsurface area contacting a part. By not requiring all of the surface areaof the milling fixture to contact a part during a milling operation, itmay require at least one of less force, less time, or fewer operators tofit the part to the milling fixture.

Parts with large surface areas may be more difficult than desirable tofit and secure in conventional milling fixtures. Concave or convex partshapes may be difficult to fit on conventional tools due to at least oneof tolerance stack up or variances in manufacturing. Conventionalmilling fixtures that are convex or concave with large surface areas mayrequire complex methods to restrain a part to contour. Parts may bescrapped because of inconsistencies caused by improper seating on aconventional milling fixture.

A reduced surface area contacting a part may allow the part to moreeasily fit in a milling fixture. A reduced surface area contacting apart may enable easier attainment of vacuum hold. Yet further, the costof the milling fixture fabrication may be reduced. For example, the costof fabrication of the milling fixture may be reduced by lessening theamount of manufacturing and inspection time to fabricate the tool. Areasof the milling fixture not requiring contact with the part may either beremoved, or the recessed areas may be given a larger tolerance value.With a larger tolerance value, the recessed areas may require lessmachining time. Further, with a larger tolerance value, the recessedareas may not require precision inspection. A further cost savings mayoccur by eliminating re-machining of a tool in the recessed areas to geta part to fit. A reduced surface contact area may reduce or preventdowntime while the tool is being re-machined. Further, a reduced surfacecontact area may reduce or prevent delays as re-machining a tool maydelay part delivery.

The description of the different illustrative embodiments has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different illustrativeembodiments may provide different features as compared to otherillustrative embodiments. The embodiment or embodiments selected arechosen and described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

What is claimed is:
 1. A method of creating a milling fixture, themethod comprising: manufacturing a first surface of a tool, such thatthe first surface comprises a first perimeter and a shape formedcomplementary to a first portion of a part for a milling operation onthe part when the part is located within the milling fixture; andmanufacturing a second surface of the tool, such that the second surfacecomprises a second perimeter that lies within the first perimeter andrecesses away from the first surface and from a second portion of thepart with the first portion of the part contacting the first surface ofthe tool and the second portion of the part is facing and not contactingthe second surface of the tool, wherein manufacturing the first surfaceand manufacturing the second surface comprises laying up a compositematerial and wherein the first surface of the tool comprises a number ofthrough-holes for performing the milling operation on a side of the partfacing and contacting the first surface of the milling fixture.
 2. Themethod of claim 1, wherein manufacturing the first surface andmanufacturing the second surface comprises machining a material.
 3. Themethod of claim 1, wherein the second surface of the tool comprises aradiused surface of the tool.
 4. The method of claim 1, wherein thesecond surface of the tool lies within a perimeter of the first surfaceof the tool.
 5. The method of claim 1, wherein the second surface of thetool comprises a hollow portion.
 6. The method of claim 1, wherein thesecond surface of the tool comprises a perimeter that lies within aperimeter of the first surface.
 7. The method of claim 1, wherein thesecond surface of the tool comprises a hollow portion and a perimeterthat lies within a perimeter of the first surface.
 8. A method ofcreating a milling fixture, the method comprising: manufacturing a firstsurface of the milling fixture comprising a female shape for contactingwith and complementary to a first portion of a part, the first surfaceof the milling fixture comprising: through-holes for milling on a sideof the part contacting the first surface of the milling fixture; and avacuum port for holding the first portion of the part in contact withthe first surface of the milling fixture; and manufacturing a secondsurface of the milling fixture by recessing the second surface of themilling fixture from the first surface of the milling fixture, a secondportion of the part facing and spaced from the second surface of themilling fixture when the part is located within the milling fixture formilling, the second surface of the milling fixture comprising a secondperimeter lying within a first perimeter of the first surface of themilling fixture.
 9. The method of claim 8, wherein manufacturing thefirst surface and manufacturing the second surface comprises laying up acomposite material.
 10. The method of claim 8, wherein manufacturing thefirst surface and manufacturing the second surface comprises machining amaterial.
 11. The method of claim 8, wherein the second surface of themilling fixture comprises a radiused surface.
 12. The method of claim 8,wherein the second surface comprises a hollow portion.
 13. The method ofclaim 8, wherein the first surface comprises an outer ring devoid ofthrough-holes.
 14. A method of performing a milling operation, themethod comprising: placing a part onto a tool such that a first portionof the part contacts a first surface of the tool and a second portion ofthe part remains recessed from a second portion of the tool, such thatthe first surface comprises a first perimeter and a shape complementaryto the first portion of the part, and the second portion of the toolcomprises a second perimeter that lies within the first perimeter and asecond surface configured to be recessed from and not contacting thesecond portion of the part when the part is located within the tool;holding the first portion of the part against the first surface of thetool; performing a number of milling operations on the part; andperforming the number of milling operations on a side of the part facingthe tool.
 15. The method of claim 14, wherein the second surface of thetool comprises a perimeter within a perimeter of the first surface. 16.The method of claim 14, wherein the second surface comprises a hollowportion and a perimeter within a perimeter of the first surface of thetool.
 17. The method of claim 14, further comprising: performing,through through-holes in the first surface, the number of millingoperations on a side of the part facing the tool.